Biomass, especially lignocellulosic biomass, is an important raw material and can be processed into fuels or industrial chemicals. Current art technologies are very time consuming and hence, capital intensive. Supercritical solvents, such as supercritical water and supercritical carbon dioxide, have been used in extracting various substances and facilitating chemical reactions. The useful applications of these value-added products increase the importance of supercritical fluid technology. Modifications to prior art techniques are needed to improve the efficiency of converting of biomass from renewable resources and/or waste materials to more valuable products. The methods and apparatus of the present invention are directed toward these, as well as other, important ends.